Sound reproducing and recording apparatus



w. M. SMITH. vSOUND REPRODUCI NG AND RECORDING APPABAT USw APPLICATION FILED MAY I9, I920.

2 SHEETS-SHEET I.

' PatentedJune 28,1921.

sduun nmo mun Ammus.

UNITED STATES 'WILLIAMV MACDONALD SMITH, 0F BLOOMSBURY, ENGLAND.

SOUND REPROD'UCING AND RECORDING APPARATUS.

Specification of Letters Patent.

Patented June 28, 1921.

Application filed May 19, 1920. Serial No. 382,600;

To all w ham it may concern:

Be it known that'I, VVILLIAM MACDONALD SMITH, a subject of His Majesty the King of England, and resident of Bloomsbury, in the county of London, Kingdom of England, have invented certain new and useful Improvements in or Relating to Sound Reproducing and Recording Apparatus, for which I have filed applications in Great Britain, No. 2125, Jan. 28, 1919, Great Britain, No. 7 013, Mar.20, 1919, Patent N0."14L3,9l7, not yet sealed, of which the following is a specification.

This invention relates to sound producing, reproducing and recording apparatus, such as those of gramophones, phonographs, harmonium and other wind instruments, microphones, telephone transmitters and receivers and the said invention has for its object to provide means for converting the ordinary harsh tone as heard in a gramophone for example and as produced in the sound-box into a pure or approximately pure musical tone.

The invention is hereinafter described with reference to its application to the sound box of a gramophone from which the nature of its general application will be readily understood.

T have found that a tube of jelly has the property of allowing free passage and rein forcement of regular vibrations (musical tones) but not of irregular vibrations (noise). The chief source of these irregular vibrations in the sound-box or casing containing the diaphragm is the narrow chamber between the diaphragm and the sides or walls of the box or casing which produces the noise by its interference with the regular musical waves of tone produced by the movements of the diaphragm.

According to this invention a chamber is provided on the side of the sound-box remote from the diaphragm, the said chamber being inclosed by a mass of gelatin, jelly or similar substance applied to, or arranged adj acent to the diaphragm; or the diaphragm may be inclosed in the usual casing which may be provided with a lining of gelatin, jelly or similar substance of suitable thickness. The consistency of the jelly is such that it readily retains the form to which it has been shaped. A hole or holes is or are provided in the jelly chamber or lining through which the sound waves caused by the vibrating diaphragm pass immediately after their production, the said sound waves being further purified, if desired, by passing In the practical application of the invention a mass of non-sonorous material such.

as jelly of suitable consistency, gelatin, soft rubber or other non-sonorous material is mounted in a casing or on the diaphragm contained in the sound box or on a partition arranged at a suitable distance therefrom or the mass of gelatin or jelly may be retained 1n position adjacent thereto by any suitable means. One convenient way of mounting the non-sonorous material in jelly form adjacent to the diaphragm consists in inclosing the non-sonorous jellymass in a casing which may be secured tothe sound box by screws; or the jelly mass may be heated and thereafter caused to adhere to the diaphragm. If so desired, the non-sonorous jelly mass may be mounted on the diaphragm by means of adhesive, or other suitable means.

The jelly mass is of any desired external form, the interior being hollow and having a centrally arranged opening throughout its depth. The said central opening is preferably of circular or elliptical form at the outer or horn end, tapering inwardly toward the diaphragm and ending at a short distance from it, in a slotor slit of suitable length and width. The slot or slit maybe approximately one millimeter wide and two centimeters long. On each side of the material through which the said central opening extends and at or about the level of. the

slot or slit is a hollow space formin a pocket with its mouth toward the diaphragm, the said pocket having the effect of leaving a thin mass of jelly on each side of the slot or slit. The material adjacent the inner end of the space surrounding thewall of the central opening is beveled or flared outwardly or inwardly, and the hollow interior of'the jelly mass may be protected at the diaphragm end with a disk ordomeshaped disk, the latter disk having, if so de-.

sired, a central hole and being attachedto the diaphragm, the said disk being formed of jelly, gelatin, softrubberor other nonsonorous material. The lips which form the slot or slit may be outwardly bulged on the side farthest from the diaphragm, and the lips adjacent the slot or slit may be beaded or of rounded form.

Instead of the usual rubber gaskets clasp the diaphragm at the circumference,

the diaphragm may be held or clasped between gaskets of non-sonorous material such a horn or tone arm of hollow semicircular or approximately crescent shaped cross-secas jelly, gelatin or other like material.

If so desired a fine helical spring be connected at one end to the exterior wall of the mass of jelly, the other end of the spring being inserted into. one or other of the lips of the slot or slit terminating the central opening to maintain the slot at its proper width or if found advantageous I may usetwo fine helical springs each having one end insertedinto the outer wall of thelnon-sonorousma ss, the other end of each spring'being' inserted into one of the lips of theslot or slit at the inner end of the central opening; ora spring may be" otherwise disposed to produce the same effect.

Inorder to-efi'ect a further purification in the tone I prefer in'combination wlth the aforesaid'chamber or chambers to use tion; a horn or tone-arm of this section may be produced by filling up -the lower portion of the interior of the usual horn or tone arm of circularsection with jelly, gelatin, or other 'non-sonorous material to or near the level of the center thereof ;'*-or such circular horn maybe providedwith a partition extending centrally throughout its length so as'to di-' vide the horn into two portions. The partition may be plane on each side or of len-' ticular'form such as bi-convex, the material forming the partition being of non-sonorous 'material as jelly, gelatin or other suitable substance.

I prefer, however, to efi'ect the shaping of the horn to the desired form when being manufactured.

The jelly employed maybe gelatin, table jelly orother similar material with or without water and the chamber, may be formed by slightly heating and shaping or molding the jellyfand thereafter applying the jellyin the desired form-to the diaphragm, orinany other suitable manner.

I will describe with'referenc'e to the accompanying drawing aconstruction-in ac- 7 mass and Figs. 6' and 7 are detail views hereinafter more fully described. 7 7

Figs. 8 and 9 show cross sections of modified forms of horns. I

Referring to Fig. 1 of the drawing, 1 is the sound-box having the usual diaphragm 2, needle support 3 and needle 4,4 indicating a record with the needle 4 in position thereon. Attached to the internally projecting rim of the sound-box 1 is a casing 5 containinga mass 6 of gelatimtable jelly or other similar material and between the casing 5 and the sound-box is interposed a washer 7 of fiber or other suitable mate-- rial. Between the washer 7 and the diaphragm 2 is a rubber gasket 9. The casing 5 and washer 7 are maintained in position by screws 8 and the washer 7 bears against. the gasket 9v which bears against the diaphragm 2. The central portion of the, washer? is cut-out or otherwise made in the form of an elliptical hole as showni'n. front elevation in Fig. 6, :and the adjacent face of the diaphragm isprovidedfwith a' centrally arranged thin disk washer 9 0 f gelatin, table jelly or other suitablematerial 'soas to damp the movement of the diaphra m and-obviate interfering: vibrations. f the disk 9 be of cup or domeshaped. form a central hole is provided therein to allow the vibrations to pass there.-

through.v The "washer .7 is provided on the face adjacent the diaphragm 2 and inwardly of the rubbergasket 9 with a circular lever 10 of soft gelatin, table jelly or other similar material having a central hole corresponding to the elliptical hole in the fiber 'washer 7 The outer face of the said'layer of soft gelatin, table jelly or other similar material may, if so desired, touch the adjacent face of the diaphragm but is preferably clear thereof. r 1

In the interior of the casing 5 is arranged the mass 6 of gelatin, table jelly, or other similar material so shaped as to form a chamber having a central outer hole 11 and a flared opening 12 adjacent the "diaphragm 2 the space between the twoopenings' being shaped as hereinafter described.

The gelatinor jelly mass 6 may be of any erably of hemispherical formexternally so that the said mass can be easily retained in position adjacent the diaphragm by the casing 5. The outer central-hole 11 adjadesired external formbutas shown isprefcent thehorn end is preferably of'elliptic formas shown in Fig. 4 tapering inwardly toward thefdiaphragm 2, and endingin a slit 13 at asuitable distance from the diaphragm. Theslit 13 may beof' any suitable and at or about the level of the slit 13 is a space 10- forming a pocket extending circularly or semi-circularly of the gelatin or jelly mass and having its mouth toward the length and widthbutithas been foundthat diaphragm, thus having the effect of leaving only a thin mass of gelatin or jelly around the slit 13. The space 10 which may be continuous circularly is preferably blocked on two diametrically opposite sides. The material adjacent the inner end of the space surrounding the slit 13 may be beveled or flared outwardly, 0r inwardly as shown at 12 Figs. 2 and 3 and thehollow-interiorof the gelatin or jelly mass may beprotected by the disk 9 or a dome-shaped disk attached to thediaphragm. The lips 16, of the slit 13 may be outwardly bulged on the side farthest from the diaphragm so'as to form a circular pocket 17 or recessadjacent the central hole 11.

The gelatin mass so shaped is practically of a hemispherical form having a hollow interior provided with a pendulous mass projecting from its interior toward the diaphragm and having a slit or slot at the end adjacent the diaphragm.

If so desired a fine helical spring 18maybe connected at one end 19 to-the exterior wall of the gelatin, or jelly mass the other end of the spring being inserted into one or other of the lips 16 of the slot or slit 13 terminating the central opening so as to maintain the slot or slit at its proper width: or I may, as shown, use two fine helical springs each having one endinserted into the outer wall of the non-sonorous gelatin mass, the other end of each spring being, inserted into one of the lips of the slot or slit terminating the inner end of the :central opening.

In order to effect a further purificationv in tone I prefer, in combination with the chamber constructed as hereinbefore explained, to use a horn ortone arm of hollow semi-circular or crescent shaped cross section as'shown in Figs. 8 and 9 respectively. A tone arm or horn of this section'may be produced byfilling up the lower portion of the interior of the'usual horn or tone arm of circular section with gelatin or other nonsonorous material to the level of the center thereof as shown at 20; or such circular horn may be provided with a partition 21'extending. centrally throughout its length. so as to divide the horn into two portions. The partition may be plane on each side or of lenticular form such as bi-convex as shown in Fig. 9, the material forming the partition being of non-sonorous material as gelatin, jelly or other suitable substance. I prefer, however, to effect the shaping of the horn to the desired sectional form when being manufactured.

The gelatinous mass may be composed of 30 to 50 per cent. of glycerin and to 50 per cent. of ordinary table jelly. The mixture may be rendered impervlous to heat and moisture by adding 10 per cent. of commercial formaldeyde to the mixture before pouring the latter; or the mixture of jelly and glycerin when shaped may be soaked in commercial formaldehyde containing 50 per cent. water for a period of or about one hour.- I .7 A chamber is thus provided on the side of the sound-box remote from the needle which chamber acts to eliminate harshness and renders the tone a pure or approximately pure musical tone. i"

I desire it to be understood that I do not limit myself to-the precise form of chamber hereinbefore described, such form being described as one example of a chamber in accordance with the present invention.

What I claim is r 1. A tone purifying device for use on gramophones, phonographs, microphones, telephone transmitters and receivers comprising a mass of non-sonorous material of cup shaped lfOI'Hl suitably mounted and re tained in position adjacent the diaphragm of such apparatus or instrument, the said nonsonorous mass havinga tubular member projecting from the interior thereof toward the diaphragm and having a central opening to admit of the sound waves passing therethrough. 4

2. A tone purifying device. for use on gramophones, 'phonographs, microphones, telephone receivers and transmitters comprising a mass of non-sonorous material of cup-shaped form suitably mounted and .retained in position adjacent the diaphragm of such apparatus or instrument, the said non-sonorous mass having a tubular member projecting from'the interior thereof toward the diaphragm and having a central opening to admit of the sound waves passing therethrough, said tubular member terminating in a slot or slitadjacentto the diaphragm.

3. A [tone purifying device for use on gramophones, phonographs, microphones,

telephone; I'QCGIVGIS and transmitters comprising ;a 'mass of: non-sonorous material mounted and retained in position adjacent the diaphragm of suchapparatus or instruw ment, the said non-sonorous.mass'having a tubular member projecting fromthe interior thereof toward the diaphragm and having a central opening to admit of the sound waves passing therethrough, said tubular member terminating in a slot or slit adjacent to the diaphragm and said non-sonorous mass having an annular space surrounding the slit end of the tubular member.

4:- A tone purifying device for use on gramophones, phonographs, microphones, telephone receivers and transmitters comprising a mass of non-sonorous material of cup-shaped form suitably mounted and retained in position adjacent the diaphragm of such apparatus or instrument, the said nonsonorous mass having a tubular member pro- 40 diaphragmand having a central Opening to admit of sound waves passing therethrough,"

jecting from the interior 'thereoftow'ard the diaphragm and having a central opening to admit of the sound waves passing therethrough, said tubular 'member terminating in a slot or slit adjacent the diaphragm and having an annular space surrounding the slit end and an annular'spacein the interior disposed in front of a centrally arranged opening at the end of the said non-sonoro'us mass remote from the diaphragm; I V 5. .T he combination with a gramophone,

' phonograph, vmicrophone, telephone receiver or transmitter, ofa hollow mass of non-sonorous material suitably mounted andlretain'ed in position adjacent the, vibrating diaphragm of the instrument and shaped to 'form a chamber to admit of sound waves passing therethrough," and a centrally arranged disk of non-sonorous material se-v cured to the dlaphragm on the emissive side thereof.

6. The combination with a gramophone,

phonograph, microphone, telephone receiver or transmitter, of a hollow mass of non-sonorous material suitably mounted and re-.

tained in fposition adjacent the vibrating diaphragm of'the instrument and shaped to form a chamber to admit of sound waves passing therethrough, and a centrally arranged disk of non-sonoro'us material securedto the diaphragm on theemis'sive side thereof and provided with a central opening, 7 The combination with a gramophone,

- phonograph, microphone, telephone receiver or transmitter, of a mass of n'on sonorous material of cup-shaped f0rm"suitably mount-' ed and retained'in position adjacentthe dia phragm of such instrument, the said nonsonorous mass having a tubular member projectmg from the interior thereof-toward the and a fiber washer havin'ga layer of nonsonorous'material on the side adjacent the diaphragm intermediate the first-mentioned non-sono'rous massand the diaphragm;

8. The combination witha gramophone, phonograph, microphone, telephone receiver or transmitter, of a mass of non-sonorous material of cup-shaped formsuitablymounted and retained in position adjacent the diaphragm' of; such] instrument, the said nonsonorous mass having a tubular member projecting from the interior thereof toward the diaphragm and having a central opening to admit i of sound-"waves passing there'- through, a fiber washer'havi-ngialayer of non-sonorous material on the sld'e adjacent the' diaphragm intermediate the first-mentioned non-sonorous imas's and the dia- 'phragm, and a gasket interposed between the fiber washer and the diaphragm and bearing against the latter. r 7 I "9. A tone purifying device for use on .g'ramophones, phonographs, microphones,

shaped toform a chamber to admit of the" sound waves passing therethrough,said nonsonorous" material consisting 0f g6lat1I10llS 'material composed'of gelatln and glycerin in or about the proportions' of 30 to 50 per cent.-of glycerin and 70'to 50 per cent.

of gelatin. V

11. A tone purifying device for use on gramophones, phonographs, microphones,

telephone receivers and transmitters 'comprising a hollow mass of non-'sonorous material, suitably mounted and retainedin position adjacent the vibrating diaphragm and shaped to form a chamberto admit of the soundwaves passing therethrough, said non-sonorous material being composed of a gelatinous material heat and moisture.

In witness I whereof name. i p

WILLIAM LVMAODONYALD SMITH: V

rendered impervious to.

I: hereunto sign my 

